Shedding light on 12 billion years ago

PUBLISHED : Sunday, 26 June, 2011, 12:00am
UPDATED : Sunday, 26 June, 2011, 12:00am


If a satellite in outer space detects bursts of cosmic light billions of light years away on Gerald Fishman's watch, he drops everything.

He will drive to the Marshall Space Flight Centre, Nasa's stakehold in Huntsville, Alabama, and look on the computer to see exactly where in the sky the burst of light, called a gamma-ray burst (GRB), occurred. The word goes out and astronomers point their telescopes at the location to see the optical light.

However, they must all move quickly. Although GRBs are the brightest events in the universe, a million times brighter than a supernova, the light dies very quickly. If the telescopes can't find the burst within the first few hours, it becomes difficult to observe. After a few days it is almost impossible to see.

Yet why do they matter? Fishman, who shared the US$1 million 2011 Shaw Prize in astronomy with Enrico Costa in Hong Kong, for their work on GRBs, sheds some light of his own.

What is the significance of GRBs?

The farther away something is, the older it is. It turns out that the light from galaxies where many GRBs are seen are from when the universe was only 10 per cent of its current age. [The best estimate for the age of the universe is about 13.7 billion years.] Light from the galaxies took 12 billion years to come to earth, so by studying the light from these galaxies, we can tell something about the types of stars and types of elements that existed in these galaxies when the universe was only one billion years old.

GRBs are known as 'high energy bursts'. How high-energy are they?

If you took the entire energy of the sun over its entire lifetime (we think the lifetime of the sun will be about 15billion years), that same amount of energy comes out of a single GRB.

How were GRBs discovered?

GRBs were discovered by small US nuclear-bomb-detection satellites that were placed into orbit in order to assure compliance by other countries with the Nuclear Test Ban Treaty of the 1960s. Since that time, the GRB detectors that observe GRBs have become larger, more accurate, and cover a larger energy range.

How do you conduct your research?

My research in astrophysics involves observations of gamma rays and X-rays coming from various types of high-energy astronomical objects in our galaxy and far beyond. These high-energy objects include black-hole and neutron-star systems, active galaxies and, my speciality, gamma-ray bursts. We make these observations with custom-built, sophisticated 'detectors'.

Because X-rays and gamma rays do not penetrate the earth's atmosphere, these high-energy detectors are placed aboard earth-orbiting satellites. Observations are performed remotely, instructions for operating and pointing the instrument are uploaded via ground stations, and the resulting data are transmitted to the ground stations for analysis by high-energy astronomers and students.

When did you start becoming interested in science?

I have always been interested in science ever since I was a little boy. I would take things apart and I had things like chemistry sets I would play with. Interest in astronomy didn't really develop until college, Bryce University. I started doing experiments or observations in gamma-ray astronomy. When I first started doing this in 1965, it was a new field; people had never made observations in the gamma ray part of the spectrum.

How do you think studying space contributes to humanity?

This type of research is purely basic research. It is just to expand our knowledge. It does not have any practical application. But, from our experience, we know that new discoveries in science may lead to eventual applications.

There are many examples, like the laser and the transistor; people looking for other things or just trying to advance basic knowledge of science came up with something new.

Mankind wants to know what his world is like and what his universe is like. The new frontier of exploration is outer space and finding out what's in the universe.

Some people said GRBs may damage earth from 2012. What do you think?

I do not believe in any predictions of coming disasters. But if a GRB were to occur relatively nearby in our galaxy, and the jet were pointed toward earth, then it would dramatically alter (or even kill) life forms on earth.

Some scientists believe that such events occur quite often. There is no way to predict when this might occur next. Some scientists further state that such an event may have been responsible for past mass extinctions on earth, such as the one that killed the dinosaurs.